1. Field of the Invention
The present invention relates to a method for inhibiting angiogenesis using a peroxiredoxin II (Prx II) inhibitor, and a method for preparing angiogenesis-inhibiting medicines using Prx II inhibitor.
2. Description of the Related Art
In signal transduction pathways involved in vasculature, PDGF/PDGFR-β (platelet-derived growth factor/platelet-derived growth factor receptor-β) and VEGF/VEGFR-2 (vascular endothelial growth factor/vascular endothelial growth factor receptor-2) (also called KDR/Flk-1) signaling pathways are important growth factor signaling pathways that modulate proliferation, chemotactic migration, and survival of VSMCs (Vascular Smooth Muscle Cell) and VECs (Vascular Endothelial Cell) (Olsson, A. K. et al., Nat. Rev. Mol. Cell Biol., 2006 7(5): 359-371; Heldin, C. K. and Westermark, B. Physiol, Rev., 1999 79(4): 1283-1316). VEGFR and PDGFR belong to the same receptor tyrosine kinase (RTK) subclass that has seven extracellular immunoglobulin-like domains, a transmembrane domain, and a split kinase domain. They share many downstream signaling events.
Recently, reactive oxygen species (ROS) such as superoxide (O2−) and hydrogen peroxide (H2O2) are known to perform a pivotal function as a secondary mediator in receptor-mediated signaling (Rhee, S. G., Science, 2006 312(5782): 1882-1883; Finkel, T. Curr. Opin. Cell Biol., 2003 15(2): 247-254). Interestingly, PDGF is the first growth factor inducing generation of intracellular ROS in vascular smooth muscle cells (VSMC) (Sundaresan, M. et al., Science, 1995 270(5234): 296-299). In the previous pioneering studies of the present invention, catalase was used to reveal that ROS, H2O2 is induced by growth factors, and participates in receptor-mediated signaling. Subsequently, a relationship between the receptor-mediated ROS production and its downstream signal transduction pathways was reported (Lander, H. M. FASEB J., 1997 11(2): 118-124), and numerous studies suggested that the oxidative inactivation of protein tyrosine phosphatases (PTPs) is located downstream of the above described signaling pathways (Rhee, S. G. et al., Sci. STKE., 2000: 2000(53)). ROS is also involved in VEGF/VEGFR-2 signaling as well as in angiogenesis (Roy, S. et al., Free Radic. Biol. Med., 2008 44(2): 180-192; Abid, M. R. et al., J. Biol. Chem., 2007 282(48): 35373-35385; Colavitti, R. et al., J. Biol. Chem., 2002 277(5): 3101-3108). It was suggested that NADPH oxidase is a ROS-generating enzyme in two RTK (VEGFR and PDGFR) signaling pathways (Ushio-Fukai, M. Antioxid. Redox Signal., 2007 9(6): 731-739; Bae, Y. S. et al., J. Biol. Chem., 2000 275(14): 10527-10531). However, there have been no studies on endogenous ROS regulators and mode of ROS action in VEGF signaling pathways.
Mammalian 2-cys peroxiredoxin (2-cys Prx) groups, belonging to the superfamily of alkyl peroxide reductase/Prx oxidoreductase, are a new type of oxidoreductase that reduces ROS into its corresponding alcohols. They reduce H2O2 into water using electrons produced from an electron-conveying system consisting of thioredoxin and thioredoxin reductase (Rhee, S. G. et al., Curr. Opin. Cell Biol., 2005 17(2): 183-189). Among five mammalian 2-cys Prx isoforms, two cytosolic isoforms, Prx I and Prx II are reported to be involved in receptor-mediated signaling pathway (Rhee, S. G. et al., Curr. Opin. Cell Biol, 2005 17(2): 183-189). In particular, the present inventors recently revealed that Prx II is a negative endogenous regulator of H2O2-mediated protein tyrosine phosphorylation in PDGF signaling (Choi, M. H. et al., Nature, 2005 435(7040): 347-353). According to this report, intracellular H2O2 level is increased and autophosphorylation of PDGFR-β at positions Tyr 857 and Tyr 579/581 is selectively increased in response to PDGF-BB in Prx II-deficient embryonic fibroblasts and vascular SMCs. Subsequently, phospholipase C-γ1 activity is increased, and cell proliferation and chemotactic migration are increased in response to PDGF-BB. It was also suggested that the inactivation-reactivation cycle of membrane PTF (Protein-Tyrosine Phosphatase) is located downstream of selective regulation of PDGFR-β phosphorylation by Prx II (Kang, S. W. et al., Trends Mol, Med., 2005 11(12): 571-578).
Meanwhile, studies for inhibiting angiogenesis have been focused on inhibition of VEGF (vascular endothelial growth factor) signaling. In fact, studies have shown that tumor cells are inhibited at an early stage, but often become more aggressive after anti-angiogenic therapy. Further, the conventional angiogenesis inhibitors inhibit even the delivery of other anticancer agents into tumor cells, and consequently tumor cells become more aggressive.
The present inventors have made many efforts to develop a novel angiogenesis inhibitor. They found that deficiency of intracellular 2-cys peroxiredoxin (2-cys Prx), especially, peroxiredoxin II (Prx II), suppresses VEGF-induced angiogenesis so as to inhibit angiogenesis and induce cancer cell death simultaneously, unlike the known mechanism inhibiting angiogenesis only. Therefore, they also found that angiogenesis inhibition and cancer cell death can be simultaneously achieved by inhibition of one target, and various angiogenesis-related diseases, ailments, or conditions, as well as cancer, can be prevented or treated, thereby completing the present invention.